Unfortunately, that method call doesn't fully include everything that is done by the com.day.cq.wcm.core.impl.commands. AbstractCopyMoveCommand class which handles the request from the UI. To fully simulate the UI, you would have to internally fire off this request using the SlingRequestProcessor.

See this article for details on how to internally fire off such a request:
http://www.nateyolles.com/blog/2015/10/get-rendered-html-for-an-aem-resource-or-component